Examine the relevance of Wegner’s theory of continental drift in explaining the present day position of 

Candidates are expected to define continental drift 

Continental drift is the movement of continental landmasses/blocks relative to one another (away, towards or alongside), across the surface of the earth to their present locations/positions to form continents such as Africa, North and South America, Asia, Europe etc. and ocean

Candidates are expected to men on Wegner’s assumptions as:

Alfred Wegner’s theory of continental drift assumptions

• Wegner’s theory is based on the rifting and drifting of continents.
• Wegner’s theory assumed that there was one giant Sialic landmass (super continent) known as Pangaea, which was located in the south near the present day South Pole, surrounded by a huge expanse of water (Ocean) known as Panthalassa
• During the Precambrian period (Permian times about 250million years) Pangaea begun rifting and drifting northwards.
• Pangaea cracked and broke into land masses i.e. Laurasia and Gondwanaland were separated by a narrow sea of Tethys (universal sea).
• At about l35million years ago, Gondwanaland and Laurasia drifted north wards leading to the closure of the Tethys Sea in the East
• Laurasia split into North America, Eurasia and Green land, Iceland while Gondwanaland split into Africa, South America, India, Austria and Antarctica.
• During the drifting the Oceans between the continental blocks became wider, forming the present day ocean basins like Atlantic, pacific etc.
• In the North, Eurasia drifted East wards.
• In the South, Africa moved to attain its present locations astride the equator.
• India drifted northwards to join Eurasia.
• South America drifted westwards and Northern wards to join north America
• Australia drifted Eastwards, away from Antarctica about 65million years ago.

Relevancy/Evidences to support Wegner’s theory

• • Jigsaw/Visual fit of continents. There is a close fitting (Jigsaw puzzle) of the continental coastlines across the Atlantic ocean i.e. the East coast of South America and West coast of Africa have good visual fit (ach fit into one another) not only at the surface but also at 2000m deep.
  • Geometric fit of continents. The west coastline of Africa and the Eastern coastline of South America fit almost exactly on each other if rotated at an angle of 57⁰ with rotational point 40⁰N and 30⁰ E
  • Matching geological/similarity in rocks and rocks bearing minerals which appear continuous. E.g. Africa and South America have rocks with a convincing boundary joined between Accra and Saolouis in Brazil, the coal bearing rocks of Eurasia and North America (the Appalachiana). The gold bearing rocks of West Africa (Ghana) and South America (Guyana).
  • Similar oil beds. Oil beds in Brazil are similar to those of Angola in Africa.
  • Matching orogenic zones/belts. The alignment of the belts of fold mountains matches across the joint of Africa and America e.g. folded ranges in Falkland Islands and Argentina are similar in age and structure to those of the south west cape of South Africa-the cape ranges.
  • Glacial evidence (Dwyka Tillite) thick deposits of tillite (fossilized glacial moraine) in Eastern Brazil, Paraguay and Argentina, are exactly like those of South Africa and Australia implying that the continents at one time were near or too close to each other.
  • Similar sedimentary Basins. A long part of North Eastern Brazil coast, South Nigeria and Cameroon, similar sedimentary rocks sequences exist and the low beds of that basin match exactly on both continents.
  • Similarity in plant and animal species in Australia and south Africa; Africa And south America
  • Palaeomagnetic evidence; Palaeomagnetism refers to ancient or foddil magnetism in rocks. It’s based on the fact that igneous rocks when cooled retain some magnetic properties which at time of magnetization point the earth’s north-south. However, studies indicated that India, Australia, South America, the magnetic properties in the magnetized rocks no longer point in the north-south direction as it should be suggesting that during the course of drifting, rocks were twisted and changed direction.
  • Existence of laterites in North America and Europe proves that these continents experienced tropical climatic conditions for formation of laterites. But with time drifted to the temperate region.
  • Existence of coral reefs in the Green land, Britain, North America and yet coral reefs form in hot climatic conditions.
  • Salt evaporites/beds in cold parts of U.S.A, Britain, Germany and Russia is evidence for continental drift from tropics because salt evaporites occur in tropics
  • Proximity of continental land masses to the North Pole than in South Pole.
  • Existence of Fold Mountains justifies the theory of continental drift. Fold mountains form when there are compressional forces acting in the same direction e.g. Mt. Himalaya
  • Identical fossils on different continents for example the ancient reptile mesosaurus are only found in southern Africa and South America yet it is not evident that it swam across Atlantic  ocean